Locate the battery compartment on the garage door opener unit or backup battery pack
Unplug the opener from power if needed
Open the battery compartment cover
Remove the old battery
Disconnect the battery terminals or unplug the battery connector
Insert the new battery with the correct polarity
Reconnect the battery terminals or connector
Close the battery compartment cover
Plug the opener back in if it was unplugged
Test the opener to confirm it works properly
Dispose of the old battery according to local regulations